Note: Descriptions are shown in the official language in which they were submitted.
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ALTERNATE PATH MANIFOLD LIFE EXTENSION FOR EXTENDED REACH
APPLICATIONS
CROSS-REFERENCE TO RELATED APPLICATION
The present document is based on and claims priority to U.S. Provisional
Patent
Application Serial No. 62/635,188, filed February 26, 2018, which is
incorporated herein
by reference in its entirety.
BACKGROUND
[0001] Gravel packs are used in wells for removing particulates from
inflowing
hydrocarbon fluids. Generally, a completion having a sand screen assembly or a
plurality
of sand screen assemblies is deployed downhole in a wellbore and a gravel pack
is
formed around the completion. To facilitate the gravel pack, the completion
may include
an alternate path system to help prevent premature slurry dehydration in open
hole gravel
packs. An alternate path system utilizes transport tubes and packing tubes
which provide
an alternate path for gravel slurry delivery. The transport tubes deliver
gravel slurry to
the packing tubes via crossover ports. However, directing the gravel slurry
into the
packing tubes can cause erosion of the packing tubes which can sometimes lead
to holes,
fractures, and/or other packing tube damage.
[0002] Attempts have been made to resist erosion by cladding an exterior
of the
packing tube at a location downstream of the crossover port. However, the
material of
the packing tube remains subject to erosive flow internally of the cladding.
Once the
packing tube material is thinned out sufficiently, the packing tube can lose
its pressure
bearing capacity and cracks can develop in the relatively brittle cladding
material. As a
result, the packing tube can burst under the pressures reached during packing
of relatively
lengthy wellbores. Additionally, some cladding processes involve inserting an
end of the
packing tube into the structure containing the crossover port and then welding
the
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packing tube to the structure. Subsequently, cladding material is added, but
this can
result in a time-consuming and expensive manufacturing process.
SUMMARY
[0003] In general, a system and methodology are provided for
facilitating
formation of a gravel pack along relatively lengthy wellbores. According to an
embodiment, a completion system comprises a screen assembly and an alternate
path
system disposed along the screen assembly. The alternate path system may
include a
transport tube and a packing tube placed in fluid communication at a manifold.
The
manifold is disposed along the screen assembly. In some embodiments, the
completion
system may comprise multiple screen assemblies with multiple corresponding
manifolds.
The packing tube is protected against erosion by a liner and a surrounding
housing which
are positioned to conduct fluid flow from the manifold as fluid flow moves
from the
transport tube, through the manifold, and into the packing tube during a
gravel packing
operation.
[0004] However, many modifications are possible without materially
departing
from the teachings of this disclosure. Accordingly, such modifications are
intended to be
included within the scope of this disclosure as defined in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Certain embodiments of the disclosure will hereafter be described
with
reference to the accompanying drawings, wherein like reference numerals denote
like
elements. It should be understood, however, that the accompanying figures
illustrate the
various implementations described herein and are not meant to limit the scope
of various
technologies described herein, and:
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[0006] Figure 1 is a schematic illustration of a portion of a completion
deployed
in a wellbore and having an alternate path system, according to an embodiment
of the
disclosure;
[0007] Figure 2 is an exploded view of a portion of an example of an
alternate
path system combining a packing tube with a manifold, according to an
embodiment of
the disclosure;
[0008] Figure 3 is a cutaway view of a portion of an example of an
alternate path
system having a transport tube in fluid communication with a packing tube
through a
crossover port in a manifold, according to an embodiment of the disclosure;
and
[0009] Figure 4 is an illustration of another example of an alternate
path system
having a packing tube coupled with a corresponding manifold, according to an
embodiment of the disclosure.
DETAILED DESCRIPTION
[0010] In the following description, numerous details are set forth to
provide an
understanding of some embodiments of the present disclosure. However, it will
be
understood by those of ordinary skill in the art that the system and/or
methodology may
be practiced without these details and that numerous variations or
modifications from the
described embodiments may be possible.
[0011] The disclosure herein generally involves a system and methodology
to
facilitate formation of gravel packs in wellbores and thus the subsequent
production of
well fluids. A well completion is provided with an alternate path system for
carrying
gravel slurry along an alternate path so as to facilitate improved gravel
packing during a
gravel packing operation. The system and methodology are very useful for
facilitating
formation of a gravel pack along relatively lengthy wellbores, such as
extended reach
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open hole wells having wellbore lengths of, for example, 4000-8000 feet.
However, the
system and methodology may be used with wells having lengths greater or less
than this
range.
[0012] In some of these relatively lengthy wellbore applications,
pressures in the
packing tubes at the heel of the completion can rise above, for example, 4000
psi and
even up to 8000 psi or more. It should be noted gravel packing operations for
these types
of longer wellbores can utilize substantially increased proppant volumes. The
increased
flow of proppant via gravel slurry as well as the higher pressures can
potentially lead to
increased erosion of the alternate path system and especially increased
erosion of the
packing tubes.
[0013] According to an embodiment, a completion system comprises a
screen
assembly and an alternate path system disposed along the screen assembly. The
alternate
path system may include a transport tube and a packing tube placed in fluid
communication at a manifold. The manifold is disposed along the screen
assembly. The
packing tube is protected against erosion by a liner and a surrounding housing
which are
positioned to conduct fluid flow from the manifold as fluid flow moves from
the transport
tube, through the manifold, and into the packing tube during a gravel packing
operation.
During a gravel packing operation, for example, the fluid flow is in the form
of a gravel
slurry carrying proppant through the transport tube and into the packing tube
via a
crossover port in the manifold. In some embodiments, the completion system may
comprise multiple screen assemblies with multiple corresponding manifolds
disposed
along a wellbore.
[0014] In various embodiments, the manifold (or manifolds) is
responsible for the
functionality enabling an alternate path system so as to achieve long distance
open hole
gravel packs. The manifold delivers slurry (which is a combination of
suspension fluid
and proppant, e.g. gravel) to the wellbore annulus by diverting flow through a
crossover
port in the manifold from transport tubes into packing tubes. The packing
tubes then
deliver the slurry to the annulus. Once the wellbore annulus is packed with
proppant, e.g.
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gravel, at a given well zone, the proppant effectively backs up through the
packing tube
all the way to the manifold. The packed proppant/gravel in the packing tubes
presents a
restriction which inhibits further flow of suspension fluid through those
packing tubes.
[0015] The restriction effectively forces the slurry to flow farther
along the
wellbore through the transport tubes and out through packing tubes in
subsequent well
zones to ensure proppant is carried to the toe of the well during lengthy
gravel packs.
Sometimes a substantial portion of the open hole wellbore may be packed via
flow of
slurry through a relatively small number of the packing tubes. This can
further increase
the chance of packing tube erosion - at least without utilizing the system and
methodology described herein.
[0016] Referring generally to Figure 1, an example of a downhole
completion 20
is illustrated as deployed in a wellbore 22, e.g. an open hole wellbore. The
downhole
completion 20 creates a surrounding annulus 24 which may be gravel packed to
enable
removal of particulates from inflowing hydrocarbon fluids during subsequent
production
operations. The downhole completion 20 comprises at least one and often a
plurality of
sand screen assemblies 26 combined with an alternate path system 28. Each sand
screen
assembly 26 may comprise a variety of components which may include a sand
screen 30
surrounding a base pipe 32.
[0017] In the example illustrated, the alternate path system 28
comprises a
plurality of shunt tubes 34 which include transport tubes 36 and packing tubes
38.
Additionally, the alternate path system 28 may comprise a manifold 40
associated with
each sand screen assembly 26 or with groups of sand screen assemblies 26. The
transport
tubes 36 and packing tubes 38 are connected to corresponding manifolds 40. As
described in greater detail below, each manifold 40 may be used to place a
transport tube
or tubes 36 into fluid communication with a corresponding packing tube or
tubes 38.
[0018] The alternate path system 28 is constructed to sustain erosive
flow of
slurry for greater amounts of proppant so as to facilitate gravel packing of
extended reach
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wells. Referring generally to Figure 2, an example of an erosion protection
system 42 is
illustrated. In this embodiment, the erosion protection system 42 comprises a
packing
tube liner 44 which is positioned in fluid communication with the
corresponding packing
tube 38. The packing tube liner 44 may be formed from a suitably erosion
resistant
material which is more erosion resistant than the material forming manifold 40
or
packing tube 38. By way of example, the packing tube liner 44 may comprise
carbide or
ceramic although other erosion resistant materials may be used in various
applications.
[0019] A housing 46 may be positioned around the packing tube liner 44,
e.g.
along an external surface of the packing tube liner 44. In some embodiments,
the
packing tube 38 may be joined to the packing tube liner 44 via the housing 46.
However,
other types of fastening techniques may be used to place the corresponding
packing tube
38 in fluid communication with the packing tube liner 44 while maintaining
pressure
integrity. Effectively, the packing tube(s) 38, housing 46, and manifold 40
are joined in a
manner which provides pressure integrity between the manifold 40 and the
packing
tube(s) 38 while housing the liner 44.
[0020] With additional reference to Figure 3, the packing tube liner 44
may be
inserted into a corresponding recess 48, e.g. a pocket, formed in manifold 40.
In the
example illustrated, at least one transport tube 36 extends through manifold
40 and is
placed in fluid communication with the corresponding packing tube 38 via a
crossover
port 50. When a gravel slurry is delivered downhole it is able to flow along
the transport
tube 36 and into the corresponding packing tube 38 via the crossover port 50.
According
to the embodiment illustrated, the packing tube liner 44 comprises an internal
passage 52
through which fluid, e.g. gravel packing slurry, may flow from crossover port
50 and into
the interior of the corresponding packing tube 38.
[0021] The erosion resistant packing tube liner 44 may be partially
inserted into
the manifold 40 via recess 48 downstream of the crossover port 50 such that
the erosion
resistant liner 44 traverses the region which may experience erosive, wall-
impinging
velocities. In some embodiments, the packing tube liner 44 may be fully
inserted into the
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manifold 40 if the recess 48 can be formed of sufficient length. As
illustrated, however,
the packing tube liner 44 also may be partially inserted into the manifold 40
such that it
extends from the manifold 40 and is enclosed and sealed by housing 46.
[0022] Effectively, the erosion resistant packing tube liner 44 provides
protection
against hotspots, e.g. high velocity impingement spots, downstream of the
manifold
crossover port 50. For example, the liner 44 provides protection at locations
along the
packing tube flow path where slurry is readjusting to a new flow path as it
transitions
from the transport tube 36 to the packing tube 38. The erosion resistant
packing tube
liner 44 is thus able to extend the life of the alternate path system 28 and
to facilitate use
of the alternate path system 28 in gravel packing extended reach wells.
[0023] In some embodiments, the erosion resistant liner 44 is protected
from
internal pressures and this capability facilitates use of the alternate path
system 28 in high
pressure applications, e.g. applications in which the manifolds 40 are
constructed with
pressure capacities up to 10,000 psi or more. The erosion resistant liner 44
may be
isolated from pressure by enclosing it within a sealed, e.g. seal-welded,
pressure bearing
cavity 54. In the example illustrated, the pressure bearing cavity 54 is
formed by recess
48 in combination with housing 46.
[0024] For example, the erosion resistant liner 44 may be partially
inserted into
the recess 48 and then housing 46 may be slid over the erosion resistant liner
44. The
housing 46 may then be seal-welded or otherwise sealed to the manifold 40. It
should be
noted the internal passage 52 of the liner 44 may have a similar shape to and
be aligned
with the downstream path created by crossover port 50. The corresponding
packing tube
38 may then be inserted into the end of the liner housing 46 (see Figure 3)
and welded or
otherwise sealably secured to the housing 46. This construction effectively
captures the
erosion resistant liner 44 within the cavity 54 formed by recess 48 and
housing 46.
[0025] Thus, when pressure is applied, the pressure is retained by the
transport
tube(s) 36, manifold 40, housing 46, and packing tube(s) 38 while the pressure
is fully
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balanced inside and outside of the erosion resistant packing tube liner 44.
The manifold
40, housing 46, and packing tube(s) 38 may be formed of similar metals to
facilitate
welding together of these components to achieve a seal between the manifold
40, housing
46, and corresponding packing tube 38 when creating cavity 54 for holding
liner 44. In
some embodiments, sealing engagement may be formed between dissimilar
materials, e.g
between dissimilar metals.
[0026] Referring generally to Figure 4, another embodiment of erosion
protection
system 42 is illustrated. In this example, the erosion resistant liner 44 is
disposed along
an end of the packing tube 38. By way of example, the erosion resistant liner
44 may
comprise at least one cover 56, e.g. plates, or cladding, e.g. carbide
cladding, disposed
along the outside diameter of the end of the packing tube 38. A portion of the
end of
packing tube 38 may be left exposed for insertion into recess 48.
[0027] The housing 46 may then be installed along the exterior of the
plating or
cladding used to form liner 44. The housing 46 may be seal welded or otherwise
sealably
attached to the manifold 40 and the corresponding packing tube 38. The sealed
housing
46 is able to maintain pressure integrity and pressure capacity even if the
wall of the
packing tube 38 erodes and exposes the plating or cladding of liner 44. In
this
embodiment, the liner 44 is once again captured in a cavity so pressure is
able to balance
inside and outside of the erosion resistant packing tube liner 44.
[0028] Depending on the parameters of a given application, the
completion 20
may have many types of components arranged in various configurations. For
example,
the completion 20 may comprise multiple screen assemblies 26 and the alternate
path
system 28 may be constructed in various arrangements. In some applications, a
plurality
of transport tubes 36 and packing tubes 38 may be coupled with each manifold
40. Each
of the packing tubes 38 may be coupled to the corresponding manifold 40 via
erosion
protection systems 42 such as those described herein. Similarly, the alternate
path system
28 may be constructed for various types of gravel packing operations over
wellbores of
various extended lengths and through differing numbers of well zones.
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[0029] Although
a few embodiments of the disclosure have been described in
detail above, those of ordinary skill in the art will readily appreciate that
many
modifications are possible without materially departing from the teachings of
this
disclosure. Accordingly, such modifications are intended to be included within
the scope
of this disclosure as defined in the claims.
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